Phase-locked loop oscillator formed entirely of logic circuits

Abstract

Phase-locked loop oscillators that are designed to set the clock rate of electronic circuits based on combinations of logic circuits and to be integrated, at the same time as these electronic circuits, into one and the same chip. There is proposed a phase-locked loop oscillator based purely on combinations of logic circuits so as not to make use of integration techniques different from those used for the electronic circuits based on combinations of logic circuits, for which they are designed to set the clock rate.

Description

1. Field of the InventionThe present invention relates to phase-locked loop oscillators and especially to those designed to generate the clock signals of an electronic circuit made on an integrated circuit chip.The performance characteristics obtained today by integration techniques enable the integration, on an integrated circuit chip, of electronic circuits based on complex combinations of logic circuits performing sequences of operations at very high rates, known as clock rates. These clock rates can no longer be distributed synchronously on printed circuit boards. This is because the time taken by the clock signals to travel from a single location to different locations of the integrated circuit chips and the dispersion between these travelling times are no longer negligible as compared with the period of these signals. This impossibility of achieving a synchronous distribution, on printed circuit boards, of the very high clock rates required by the electronic circuits integrate...

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